The ATN aeronautical telecommunication network makes it possible to ensure reliable ground/onboard digital links for information exchanges between aircraft on the ground or in flight and centers on the ground, whether the centers are endowed with an air traffic control activity, the information exchanged with the air traffic control authorities being termed ATC (the acronym standing for Air Traffic Control), or endowed with an activity of aircraft or flight operation, the information exchanged with the airline or airlines operating the aircraft which may be very diverse being termed non-ATC, the distinction between the two types of information being justified by transmission constraints that differ at the safety and reliability level.
As an example of ATC information, mention may be made of the position, heading and speed of the aircraft, and trajectory modification orders; it may also involve messages exchanged between the pilot and the air traffic controller, these messages being digitized. This information is dispatched periodically according to a predetermined frequency or upon an event.
Like any digital link, the ATN aeronautical telecommunication network allows information exchanges or dialogs between two tasks or applications run by remote processors, in general a processor placed on board an aircraft and a processor placed on the ground. Applications able to hold a dialog between themselves via the aeronautical telecommunication network ATN are termed ATC or non-ATC according to the nature of the information that they exchange.
The ATN aeronautical telecommunication network comprises an aerial part on board each aircraft hooked up and a terrestrial part.
The aerial part is composed of various sender/receiver equipment on board an aircraft. Said equipment is managed on board the aircraft by an automaton referred to as a communications management unit which, in addition to their management, undertakes the initialization, sustaining, completion and routing of a communication, the execution of air traffic control applications like the periodic communication of the position of the aircraft to the ground control and the execution of fleet management applications like the monitoring of the consumption of the aircraft.
The aircraft is generally also equipped with a surveillance system such as for example a T2CAS system (the acronym standing for the expression “Traffic and Terrain Collision Avoiding System”) which provides the pilot with information on the surrounding situation of the aircraft, which allows him to exchange information with other aircraft also equipped with the same system, and which, as appropriate, prompts him with aircraft collision avoidance or terrain avoidance maneuvers. This information intended for the crew is displayed on a ND screen (the acronym standing for the expression “Navigation Display”). Said information is very precise and recalculated each second: the distances are for example indicated with a precision of a few tens of meters.
But the communications management unit and the surveillance system do not communicate: the information of the surveillance system is not automatically transmitted to the air traffic control authority. When an avoidance maneuver is proposed to the pilot by the surveillance system, said maneuver may come into conflict with a previous order from the air traffic control authority. Although the decision concerning the maneuver is up to the pilot, a discussion generally ensues between the pilot and the air traffic control authority; but the latter does not have the same information at its disposal.
Concerning the situation surrounding the aircraft, the air traffic control authority has at its disposal information provided by ground radars: this information is provided only every six seconds and is less precise than that provided by the surveillance system. The air traffic control authority is not furnished in particular with the various choices offered to the pilot, nor of course with the situation surrounding the aircraft as seen from on board.
Furthermore, this vocal exchange between the pilot and the air traffic control authority is a source of delay in the execution of a maneuver which, however, sometimes requires a fast reaction.
An important aim of the invention is therefore to avoid these possible conflicts and source of delay concerning these avoidance maneuvers.